This study reviews the current knowledge about endometrial somatic stem cells and endometrial cancer stem cells. It describes the main features of somatic stem cells, such as high proliferative potential, self renewal, differentiation into 1 or more lineages, retention of a DNA synthesis label (BrdU), and some methods to identify them (Hoechst dye exclusion test, immunophenotyping). The most likely markers for endometrial somatic stem cells (Oct-4, Musashi-1, CD31, CD34, and CD144) are also mentioned. The study also reviews the literature regarding endometrial cancer stem cells. Results obtained by evaluation of the side population in endometrial cancer cell lines and studies on putative cancer stem cell markers are also discussed. The possible roles of endometrial cancer stem cells in metastasis and resistance to anticancer treatment are also mentioned.